Boil the potatoes in salted water until tender, about 15-20 minutes.

Drain and let cool, then chop into bite-sized pieces.

In a bowl, mix together mayonnaise, mustard, vinegar, salt, and pepper.

Add the cooled potatoes and mix until well coated.

Fold in celery, green onions, and bacon.

Chill in the refrigerator for at least 30 minutes before serving.